Chevrolet Repair: Oldsmobile cutlass, oldsmobile cutlass, cutlass supreme

Question
I have a 1990 cutlass supreme. We recently put new seals in the transmission. When you drive it, it will shift nice and smooth then all of a sudden it you slow down or come to a stop sign it seems like it is kicking itself back into to neutral. If you shift it in to park then back to drive then it will be fine again for a while and shift great then all of a sudden it will shift itself back into neutral or seems to be. Have any ideas? If so how do I go about fixing it. It has a 3.1 engine in it.

Answer
ok tyler lets fix this one....You told me that you have a 3.1 engine.If it has a vacuum line you probably have a 44t4 4 speed If it has a cable you have a 125c 3 speed.. You mentioned ''new seals'' Are we talking internal or external seals? If the transmission is a 125c you might try dropping the pan to see if the filter fell off. A very common problem!Always check the fluid level after the vehicle is warmed up...You will find that in some cases ,an extra pint ''over'' the line works well.Good luck